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Equine Health Resource

Retained Placenta

Retained placenta is a fairly common complication in mares after foaling. Normally, the placenta drops out whole within 30-60 minutes of foaling. Placentas are considered retained after 3 hours.

It is common for the tips of the placenta to tear loose and stay attached within the uterus. This is an ongoing source of contamination and infection. Mares with a retained placenta (or with these retained portions) rapidly develop life threatening uterine infections, which cause severe illness, fever, laminitis and even death.

In many cases, vets use uterine flushing and antibiotic infusion in combination with removal. Systemic antibiotics and other drugs may be used as well.

Sometimes, a part of the placenta is so well anchored inside a mare that it must be left in place for a time. In this case, special management is needed to decrease uterine infection.

After the retained placenta has been removed, your vet will give you specific instructions for follow-up including instructions regarding uterine involution, to ensure that your mare’s uterus is shrinking down normally after foaling.

Prognosis & Relevant Factors

Prognosis depends on how long the placenta is retained, the cause, and your mare's overall systemic health. Good if this condition is diagnosed and treated early. Poor once severe metritis (uterine infection) sets in.


  • What management changes can I make to reduce the likelihood of this condition in my mares?
  • Will this affect my mare's fertility?

    Avoid feeding your mare endophyte infested fescue hay late in her pregnancy (fescue toxicosis). Periodically have your mare's placental thickness evaluated by your vet during her pregnancy.

    If your mare has a history of reproductive problems, talk to your vet about conducting a uterine biopsy and other diagnostics.

    Helpful Terms & Topics in HSVGWritten, Reviewed or Shared by Experts in Equine Health

    Helpful Outside ResourcesCredible Equine Health Information on the Internet

    Author: Doug Thal DVM Dipl. ABVP


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